Trimming machines

ABSTRACT

A clamp for immobilizing sheet material being trimmed is springmounted and guided by a knife holder for advancing movement independently of the knife and is retracted or restored independently of the knife.

[451 Aug. 12, 1975 United States Patent 1 Bulka 1/1939 behmanmi...

.N. e" H mm mm mn wwma ndnmc u m c MBmM 4 3 4677 999 /HHH 7295 63686 65 86 n- 45 03 J 22 3593 m n w a .L n k a n i .l 0 n a aw m mh S M u E n a N! an I Mb 0 l n C 0 A m CD. M V. C 8 o G R MC N M U 6 m m m w n R v n T.m A NM 5 7 7 [22] Filed: Nov. 2, 1973 Primary Examiner-Frank T. Yost Attorney, Agent, or Firm-Kinzer, Plyer, Dorn & McEachran [21] Appl. No.: 412,490

[57] ABSTRACT A clamp for immobilizing sheet material being trimmed is spring-mounted and guided by a knife [52] US. Cl. 83/387; 83/389; 83/460 [51] Int. 826d 7/02 [58] Field of Search 83/389, 460, 459, 452,

holder for advancing movement independently of the References Cited UNITED STATES PATENTS knife and is' retracted or restored independently of the knife.

1,441,202 Ballard,............................. 83/459 x 5 Claims, 4 Drawing Figures PMUHEU AUG 1 2 I975 SHEET TRIMMING MACHINES This invention relates to cyclically operable trimming machines for trimming paper sheets, signatures, small books and the like. i

It is known to trim a signature (folded sheet as part of a book) at the head, foot and front, and sometimes signatures are cut in half to produce two books, also considered to be a trimming operation within the context of this disclosure.

The signature is engaged by a clamp at a point in the machine cycle just before the knife commences its cutting stroke, the purpose being of course to immobilize the signature while it is being trimmed. The knife is secured to a vertically reciprocating knife holder. The clamp is spring-supported on the knife holder and leads the knife so that the clamp first engages the signature (or sheet) as already noted. The spring support for the clamp establishes a yieldable connection, the spring means compressing during the time that the knife holder forces the knife through the sheet material being cut. On the return stroke of the knife holder, the normal arrangement is characterized by the clamp continuing to apply a holding force until the spring means is fully restored, which occurs after the knife has cleared the cut material. Thus, the clamp unnecessarily dwells on the sheet material during a portion of the return stroke of the knife holder, which is to say that the clamp could be released the instant the knife clears the signature on the return stroke, allowing the trimmed material to be fed from the knife station the instant the knife is in a retracted or clearing position. The disadvantage of the dwell or idle period has heretofore been recognized according to US. Pat. No. 3,732,766 wherein provision is made for cyclically operating the clamps independently of the knives, without using the earlier known arrangement of spring means in the knife holder to advance and return the clamp.

Experience reveals that in some instances there is an advantage in biasing the clamp with a spring means and using the knife holder as a guide for the clamp means. Accordingly, the primary object of the present invention is to relate a clamp and a spring means for the purposes described, to guide the clamp by the knife holder,

and to interpose a separate clamp drive for the clamp,

the separate drive being one capable of adjustment so that withdrawal or release of the clamp may be care fully timed to the machine cycle.

Other and further objects of the present invention will be apparent from the following description and claims and are illustrated in the accompanying drawing which, by way of illustration, shows a preferred embodiment of the present invention and the principle thereof and what is now considered to be the best mode contemplated applying that principle. Other embodi ments of the invention embodying the same or equivalent principles may be used and structural changes may be made as desired by those skilled in the art without departing from the present invention.

In the drawings:

FIG 1 is a side elevation of a machine, partly sectional, incorporating the present invention;

FIG. 2 is a front elevation of a portion of the machine;

FIG. 3 is a detail perspective, partly in section, showing a portion of the machine; and

FIG. 4 is a diagram of eccentric motion.

Referring to FIG. I the present invention is disclosed as incorporated in a trimming machine 10 having a C- shaped frame 11 extending upwardly from a floor mounted base 12. A support table indicated generally at 14 is disposed in a horizontal plane. A folded sheet constituting a signature S is disposed on the table, medially positioned or centered with respect to a stationary cutting die or lower knife 16 which defines the cutting plane. The lower knife opposes an upper, reciproeating knife 17 having a cutting edge 18.

Signatures as S are successively fed to the trimming means by feed means, not shown, of the character shown in US. Pat. No. 3,732,766.

The knife 17 is mounted on a vertically reciprocating knife holder 20 in the manner shown on FIG. 2. During reciprocation of the knife holder from top dead center to bottom dead center the knife edge 18 penetrates the signature S, severing the signature S into two parts.

Stops, not shown, accurately locate the signature S in cutting position, the stops being cyclically raised and lowered as described in U.S. Pat. No. 3,732,766. The knife holder is cyclically reciprocated as successive signatures are located in cutting position. To this end the knife holder is provided on opposite sides with a pair of links 22, FIGS. 1 and 2, the lower end of each link being pivotally mounted on a stud 23, FIG. 1, extending outwardly from one side of the knife holder. The upper end of each link 22 is journaled on a pin or stud 24 carried at the free or outer end of an arm 26. The two arms 26 in turn are secured to a rock shaft 29 such that clockwise motion of the rock shaft drives the knife holder downwardly while counter-clockwise rotation or oscillation of the rock shaft 29 returns the knife holder from bottom dead center (BDC) to its top dead center position, TDC. The construction and operation of the knife holder is well known in the art and constitutes no part of the present invention.

A clamp in the form of a bar 35 is positioned beneath the knife holder and, as shown on FIG. 1, is aligned with a portion of the die member 16 in position to bear on the top of the signature, holding the latter stationary during the cutting stroke of the knife.

Referring to FIGS. 2 and 3 a pair of guides 37 and 38 are secured vertically in spaced relation to the upper face of the clamp 35. The guides 37 and 38 are disposed in corresponding recesses 41 and 42 extending upwardly through the knife holder. The guides 37 and 38 are reduced in diameter at 37A and 38A, FIG. 2, and the upper ends thereof extend upwardly above the knife holder at 37B and 38B. Spring retainers 43 and 44 are secured to the top of the knife holder as shown in FIG. 2, the extended ends 37B and 38B of the clamp guides extending through apertures formed therein.

A pair of coil springs 45 are mounted within the recesses of the knife holder in concentric relation to the reduced portions 37A and 38A of the clamp guides. The lower ends of the springs 45 act on the guides 37 and 38 and the upper ends thereof bear against and react on the underside of the spring retainers 43 and 44.

The upper ends 378 and 38B of the clamp guides are joined by a cross head 50, the latter being retained by nuts 54 which clamp the cross head 50 to adjusting nuts 52 provided on the upper ends 378 and 38B of the clamp guides.

Reciprocation and timing of release of the clamp are under control of a cyclically operated means in the form of an eccentric 55, FIG. 1, and means are provided for translating rotatory motion of the eccentric 55 into an upward linear stroke of the guides 37 and 38 which support the clamp 35.

The eccentric is fixed to a constantly rotating shaft 56 and a strap 57 embraces the eccentric 55 as shown in FIG. 1. The strap 57 includes a sleeve 58 in which is disposed a connecting rod 60. The lower end of rod 60 is mounted loosely in a recess 61 formed in a stub I extension 62 of the strap 57.

The rod 60 extends upwardly and the upper end thereof is connected to the left or aft end of a lever 64 as shown in FIG. 1. The lever 64 is journaled on a pin or stub shaft 65 supported in a bracket 66, secured to the frame 11. A roller 68 is mounted on the opposite end of the lever 64 in position to engage an adjustable stop means 70 depending from the clamp cross head 50. More specifically the stop 70 is represented by the head of a screw 71 threadedly mounted in the cross head 50 and provided with a holder or knob 73 and associated lock nut 74. Obviously the adjustable stop as 70 may take many different forms.

A coil spring 75 surrounds rod 60 within sleeve 58, one end thereof being engaged with a collar 76 pinned to rod 60 and the other end being engaged with a collar 78 secured to sleeve 58. Spring 75 constitutes a lost motion connection for a purpose to be explained. Op eration of the apparatus will now be described.

The eccentric 55, as noted, controls movement of the clamp 35. Another eccentric (not shown) is also fastened to shaft 56 and controls oscillation of shaft 29 associated with the knife holder operating links 22. In this connection it may be noted that the eccentrics on shaft 56 may be so adjusted that during advancing movement toward the sheet or signature S the clamp leads the knife by, say, 42. Thus, FIG. 4, when the knife is at BDC (180) to cut S the clamp is already at BDC and was at BDC since 138 of the knife stroke.

As shown in FIG. 1 the low part of the eccentric 55 is presented to the strap 57 corresponding to the clamp being fully retracted at top dead center. At this time the coil springs 45 are compressed (for reasons to be explained) storing energy for driving the clamp 35 downward. As point 55A on the eccentric 55 rotates clockwise toward point 558 on the strap, FIG. 1, the strap 57 is shifted, driving rod 60 upwardly, whereupon lever 64 is rocked clockwise dropping roller 68. The springs 45 associated with the clamp guide and support structure are therefore free to expand driving the clamp 35 downwardly and such downward movement of the clamp continues under the influence of the expanding springs 45. After about 42 of rotation of the eccentric 55, the knife holder commences its downward movement and after 138 of the knife holder cycle, FIG. 4, the clamp 35 engages the sheet to hold it stationary whereafter the knife continues its advancing movement and completes its cutting stroke.

When point 55A of the eccentric 55, FIG. 1, has attained point 55B, FIG. 1, the clamp is at bottom dead center; continued clockwise rotation of eccentric 55 rocks the lever 64 counterclockwise, elevating roller 68 which raises bar 50 and guides 37-38 which in turn elevate the clamp independently of the knife and the springs 45 are once more compressed to store energy for the next downward movement of the clamp. It will be realized that at times the knife holder and clamp are moving together. On the other hand, the clamp engages the sheets to be trimmed 42 ahead of the knife .(in the example given) and the clamp is released before the knife blade has attained. BDC.

It will be recognized that .the time of release of the clamp may be very carefully selected merely by adjusting the eccentric 55 onits shaft 56. Location of stop may be varied according to whether the signature being cut is a thick one or a thin one. I

If there should be mis-timing in the adjustment manifest in clamp 35, FIG. 3, being elevated into contact with the knife holder, the spring merely compresses. Thus, if the clamp 35 is obstructed when strap 57 tends to pull sleeve 58 downward (pulling rod 60 downward by collar 78 acting on spring 75, and spring 75 acting on collar 76) then spring 75 is merely compressed between collars 76 and 78 as a lost motion connection.

It will be seen from the foregoing that under the present invention the clamp is driven independently of the knife by virtue of the spring means 45 and roller 68 controlled by eccentric 55. The spring means are compressing from the time the clamp is released from the work until the knife is retracted from bottom dead center. This occurs as the cyclically operable lever 64 is oscillated counterclockwise to elevate roller 68 which drives the clamp support means upwardly. Afterwards, when the clamp and knife are together being restored toward TDC the compression of the springs is maintained since the clamp and knife holder travel at the same speed. Then when lever 64 oscillates clockwise roller 68 in effect releases the clamp support bar 50 to the downward driving action of the spring.

I claim:

1. In a trimming machine for trimming paper sheets, signatures and like material, a reciprocal knife holder having a trimming knife mounted thereon, means to reciprocate the knife holder along a vertical axis to move the knife through a predetermined horizontal cutting plane, a reciprocal clamp disposed beneath the knife holder and guided by the knife holder for clamping the material to be trimmed, spring means for driving the clamp in one direction independently of the knife holder, cyclically operable means for driving said clamp independently of the knife holder in the opposite direction, said cyclically operable means including an eccentric which is adjustable to time operation of the clamp to the knife holder, a strap on the eccentric to be reciprocated thereby, a rod connected to the strap, the connection between the rod and strap including a lost motion spring, and means for imparting reciprocation of said rod to said clamp.

2. A machine according to claim 1 wherein the clamp includes a pair of guides secured thereto, said guides being mounted in recesses in the knife holder, and springs in said recesses acting on the clamp and reacting on the knife holder.

3. A. machine according to claim 2 wherein the guides have upper ends extending outwardly of said knife holder, a cross head joining the upper ends of said guides, an adjustable stop on said cross head, an oscillatable lever connected at one end to said rod, and a roller at the other end of said lever bearing on said cross head.

4. In a trimming machine for trimming paper sheet material, a reciprocal knife holder having a trimming knife mounted thereon, means to reciprocate the knife holder, a reciprocal clamp for clamping the sheet mate rial to be trimmed,-and means to reciprocate the clamp by said cyclically operable means if the clamp is obstructed, wherein the spring means are coil springs reacting on the knife holder and acting on the clamp, wherein the supporting means for the clamp are guided by the knife holder and wherein the cyclically operable means include an eccentric and an oscillatable lever operated by the eccentric which on oscillation in one direction drives the clamp in one direction independently of the knife holder to compress the coil springs and which on oscillation in the opposed direction frees the clamp to the spring means.

5. A machine according to claim 4 in which the eccentric is adjustable to time operation of the clamp to the knife holder. 

1. In a trimming machine for trimming paper sheets, signatures and like material, a reciprocal knife holder having a trimming knife mounted thereon, means to reciprocate the knife holder along a vertical axis to move the knife through a predetermined horizontal cutting plane, a reciprocal clamp disposed beneath the knife holder and guided by the knife holder for clamping the material to be trimmed, spring means for driving the clamp in one direction independently of the knife holder, cyclically operable means for driving said clamp independently of the knife holder in the opposite direction, said cyclically operable means including an eccentric which is adjustable to time operation of the clamp to the knife holder, a strap on the eccentric to be reciprocated thereby, a rod connected to the strap, the connection between the rod and strap including a lost motion spring, and means for imparting reciprocation of said rod to said clamp.
 2. A machine according to claim 1 wherein the clamp includes a pair of guides secured thereto, said guides being mounted in recesses in the knife holder, and springs in said recesses acting on the clamp and reacting on the knife holder.
 3. A machine according to claim 2 wherein the guides have upper ends extending outwardly of said knife holder, a cross head joining the upper ends of said guides, an adjustable stop on said cross head, an oscillatable lever connected at one end to said rod, and a roller at the other end of said lever bearing on said cross head.
 4. In a trimming machine for trimming paper sheet material, a reciprocal knife holder having a trimming knife mounted thereon, means to reciprocate the knife holder, a reciprocal clamp for clamping the sheet material to be trimmed, and means to reciprocate the clamp independently of the means which reciprocate the knife holder, said last-named means including: means supporting the clamp for reciprocal movement, spring means arranged to be compressed by movement of the clamp in one direction to store energy for driving the clamp in the opposite direction, and cyclically operable means to drive the clamp in said one direction and to release the clamp for movement in the opposite direction under the influence of the compressed spring means, said cyclically operable means including a lost motion spring to prevent the clamp from being driven by said cyclically operable means if the clamp is obstructed, wherein the spring means are coil springs reacting on the knife holder and acting on the clamp, wherein the supporting means for the clamp are guided by the knife holder and wherein the cyclically operable means include an eccentric and an oscillatable lever operated by the eccentric which on oscillation in one direction drives the clamp in one direction independently of the knife holder to compress the coil springs and which on oscillation in the opposed direction frees the clamp to the spring means.
 5. A machine according to claim 4 in which the eccentric is adjustable to time operation of the clamp to the knife holder. 